The human eye may produce optical aberrations, in which the cornea, lens, and other portions of the eye that constitute the human optical system cause light entering the eye to not be properly focused on the retina, producing a blurring of the resulting image. Generally, aberrations fall into two categories: monochromatic aberrations (e.g., defocus, astigmatism, spherical aberration, and so on), which may result in improper focusing of portions of light having different wavelengths and which may be caused by the geometry (e.g., location, shape, orientation, etc.) of various portions of the eye, and chromatic aberrations (e.g., axial aberrations and lateral aberrations), which may result in different portions of light having different wavelengths being focused at different locations within the eye.
In some cases, chromatic aberrations may be caused at least in part by portions of the eye (e.g., the lens of the eye) having different indexes of refraction with respect to different wavelengths of incident light. More specifically, axial (or longitudinal) chromatic aberration may cause light having different wavelengths to be focused at different depths or positions along the optical axis of the eye (e.g., in front of or behind the retina), while lateral (or transverse) chromatic aberration may cause light having different wavelengths to be focused at different lateral locations (e.g., along the retina).
While at least most types of significant monochromatic aberrations (e.g., defocus, astigmatism, spherical aberration, and the like) may vary greatly from one viewer to another, axial chromatic aberration may be relatively constant from one viewer to the next. Moreover, the amount of lateral chromatic aberration experienced by the viewer may depend on either or both the position of light in the pupil and the angle of incidence of the light when entering the eye.